I/OAT: fix channel resources free for not allocated channels

commit c3d4f44f50b65b0b0290e357f8739cfb3f4bcaca upstream

If the ioatdma driver is loaded but not used it does not allocate descriptors.
Before it frees channel resources it should first be sure
that they have been previously allocated.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Tested-by: Tom Picard <tom.s.picard@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index bc8c6e3470ca258f6646c0ad2cd9278425296ec2..b762db2e8073f9adf4054ad076451ebf1a653221 100644 (file)
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -801,6 +801,12 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
        struct ioat_desc_sw *desc, *_desc;
        int in_use_descs = 0;
 
+       /* Before freeing channel resources first check
+        * if they have been previously allocated for this channel.
+        */
+       if (ioat_chan->desccount == 0)
+               return;
+
        tasklet_disable(&ioat_chan->cleanup_task);
        ioat_dma_memcpy_cleanup(ioat_chan);
 
@@ -863,6 +869,7 @@ static void ioat_dma_free_chan_resources(struct dma_chan *chan)
        ioat_chan->last_completion = ioat_chan->completion_addr = 0;
        ioat_chan->pending = 0;
        ioat_chan->dmacount = 0;
+       ioat_chan->desccount = 0;
        ioat_chan->watchdog_completion = 0;
        ioat_chan->last_compl_desc_addr_hw = 0;
        ioat_chan->watchdog_tcp_cookie =